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The [functions] section allows you to manually specify function boundaries, override auto-generated names, and define discontinuous code chunks.

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Function Definition

Functions are defined using hexadecimal address keys: 
[functions."0x82000100"]
size = 0x200
name = "GameInit"

[functions."0x82000400"]
end = 0x82000800
name = "Render"

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FunctionConfig Structure

From config.h:42-54:
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functions.<address>.size
uint32
default:0
Explicit size of the function in bytes. Mutually exclusive with end.
[functions."0x82000100"]
size = 0x400  # Function is 1024 bytes
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functions.<address>.end
uint32
default:0
End address of the function (exclusive). Mutually exclusive with size.Must be greater than the start address. The function size is calculated as end - address.
[functions."0x82001000"]
end = 0x82001400  # Size = 0x400
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functions.<address>.name
string
Custom symbol name for the function. If not specified, auto-generates sub_XXXXXXXX format.
[functions."0x82000100"]
size = 0x200
name = "PlayerUpdate"
​
functions.<address>.parent
uint32
default:0
Parent function address for discontinuous chunks. When non-zero, this entry is a chunk belonging to the parent function.Use this for functions with non-contiguous code regions (e.g., cold/hot path separation).
# Parent function
[functions."0x82000100"]
size = 0x200
name = "MainLoop"

# Chunk belonging to MainLoop
[functions."0x82005000"]
size = 0x100
parent = 0x82000100

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Size vs End

You must specify either size or end, but not both: 
# Using size (preferred)
[functions."0x82000100"]
size = 0x400

# Using end address
[functions."0x82000500"]
end = 0x82000900

# ERROR: Cannot use both
[functions."0x82000A00"]
size = 0x200
end = 0x82000C00  # This will fail validation

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Discontinuous Chunks

Some compilers split functions into multiple non-contiguous regions. Use the parent field to define chunks: 
# Main function entry point
[functions."0x82000100"]
size = 0x200
name = "ProcessInput"

# Cold path chunk (rarely executed code)
[functions."0x82010000"]
size = 0x80
parent = 0x82000100  # Belongs to ProcessInput

# Another chunk
[functions."0x82010100"]
end = 0x82010180
parent = 0x82000100
Key properties of chunks:
  • Chunks have parent != 0
  • Chunks are not entry points themselves
  • Multiple chunks can belong to the same parent
  • Chunks can overlap with other functions (parent function boundaries)
  • Standalone functions cannot overlap

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Validation Rules

From config.cpp:100-124 and config.cpp:289-350:

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Address Alignment

All function addresses must be 4-byte aligned (PowerPC instruction size): 
# Valid: aligned to 4 bytes
[functions."0x82000100"]
size = 0x200

# INVALID: not aligned
[functions."0x82000101"]  # Will fail validation
size = 0x200

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Mutual Exclusivity

Cannot specify both size and end: 
# ERROR: Validation will fail
[functions."0x82000100"]
size = 0x200
end = 0x82000300

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End Address Constraint

When using end, it must be greater than the start address: 
# INVALID: end <= start
[functions."0x82000100"]
end = 0x82000100  # Will fail

# Valid
[functions."0x82000100"]
end = 0x82000200

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No Overlapping Boundaries

Standalone functions (non-chunks) cannot overlap: 
# INVALID: Functions overlap
[functions."0x82000100"]
size = 0x400  # Ends at 0x82000500

[functions."0x82000300"]  # Starts before previous ends
size = 0x200  # Will fail validation
Chunks CAN overlap with their parent function boundaries.

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Common Patterns

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Override Auto-Detection

Force specific boundaries when analysis is incorrect: 
[functions."0x82000100"]
size = 0x800
name = "ComplexFunction"

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Split Functions

Handle hot/cold code splitting: 
# Hot path (frequently executed)
[functions."0x82000100"]
size = 0x400
name = "FastPath"

# Cold path (error handling)
[functions."0x82100000"]
size = 0x200
parent = 0x82000100

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Name Important Functions

[functions."0x82000100"]
name = "main"

[functions."0x82000500"]
name = "Initialize"

[functions."0x82000A00"]
name = "Shutdown"

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Example Configuration

project_name = "mygame"
file_path = "default.xex"
out_directory_path = "generated"

# Main entry point
[functions."0x82000000"]
size = 0x100
name = "__start"

# Game initialization
[functions."0x82000100"]
end = 0x82000500
name = "GameInit"

# Main loop with cold path
[functions."0x82001000"]
size = 0x800
name = "MainLoop"

[functions."0x82100000"]
size = 0x200
parent = 0x82001000  # Error handling chunk

# Rendering system
[functions."0x82002000"]
size = 0x1000
name = "RenderFrame"

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See Also

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